Or, (and I know this will come across as a radical idea) it can focus on getting biffs better.The army could, of course, discharge some on medical grounds.
Not only does this mean there will be less biffs, but it means more facilities for the geniune cases to get better.
My first unit was 16 regt Bicester which was a static third line depot. We didn't have a 20% biff rate at junior level. (can't recall the seniors/officers cos the idle cnuts didn't turn up for PT regardless if they were fit or not)